Genotype Analysis Of Varicella-Zoster Virus (VZV) In China And The Genetic Study Of VZV Glycoprotein E

Objective Through molecular epidemiology studies on varicella-zoster virus (VZV), to determine the genotypes of VZV strain from different regions in China, and to find the molecular differences between the strains and those from other parts of the world. Another aim is to study the possible genetic mutations in the gE gene of Chinese VZV strains by DNA sequencing and the evolutionary analysis of the viral gE gene. At last, clone and prokaryotic expression the extracellular domain structure (1-539aa) of VZV glycoprotein E.Methods In the present study,318samples of skin vesicle fluid or scab chip were collected from the patients with varicella or zoster in the cities of Changchun, Beijing, Xi’an, Urumqi, Lhasa, Guangzhou and Shanghai from December2010to June2011along with the details of case history.44VZV strains isolated in Hefei from June2007to June2008were also included, which makes the total number of DNA samples of362. Genotyping was performed by SNP analysis in ORFs1,6,12,16,17,21,22,35,37,50,54,55,56,60and66. Viral gE gene was sequenced and analyzied for possible mutations. Finally, constructed the expression vector of glycoprotein E of v-Oka strain and expressed in E.coli.Results VZV DNA was detected by PCR in348samples among the total of362samples (96.1%). Genotyping of348VZV strains by SNP analysis resulted in4genotypes with the majority of clade2(89.94%), and minors belong to clade5(6.32%) and clade3(1.44%). The remaining7strains (2.01%) circulating in Changchun and Xi’an were not attributed to any genetic clade by the present menthods, strongly suggesting noval genotypes. Eighteen VZV strains representing4genotypes were selected for gE gene sequence analysis. In addition to the synonymous and non-synonymous mutions reported in the literature, there were3new non-synonymous mutations (C56T, C1109T, C917A) and4noval synonymous mutations (C54T, T1075C, T816C, G279A) found in the8strains analyzed. The expression vector of pET28-gE (1～539aa) was successfully constructed and expressed in E.coli, the size of recombinant protein was59kDa.Conclusion Genetic diversities were found among the VZV strains in China. Although89.9%of the strains belong to clade2, clades3and5were first reported in China. In addition, a few non-classified strains were found in strains circulating in Changchun and Xi’an. By analysis of gE gene sequences, we found a novel non-synonymous mutations in the el and c1epitope region, corresponding to an amino acid substitution of serine to tyrosine. The expression vector of pET28-gE (1～539aa) was successfully constructed and prokaryotic expresed gE fusion recombinant protein, and laid a foundation for the research and development of VZV subunit vaccine.